The repair shops around Moab love the D35's,
and the 35 build up kits. They say they're keepin 'em in business. Don't run anything over 33's and watch the go pedal is what I hear. You can snap axles easier with a locker than without. Differentials transfer traction to the non-traction tire, that's why your tire spins in mud & snow. The tire with traction sits while the non-traction tire spins. With a locker any pressure from traction will not transfer the load to the non-traction tire. So at any given time the entire load can go to one axle as it's got all the traction. Rather than build up a unit that's too weak and then replace it, consider replacing the unit and then build it up. It comes down to what kind of offroading you do. And how fond you are of the right pedal.
You'll like what your jeep can do with a locker, but you'll forfeit road manners.
4 wheelin, jeepin, offroadin, rockcrawlin, and a little wrench bendin